Search results for "Spark"
showing 10 items of 124 documents
Spark Plasma Sintering tool design for preparing alumina-based Functionally Graded Materials
2016
Abstract A way to produce Functionally Graded Materials (FGM) is by means of Spark Plasma Sintering (SPS) and specifically designated tools. These new tools permit a current density modulation and therefore a temperature variation along the z-axis. The key feature relies on a varying die section. FEM modelling has given the suitable range of die dimensions between the top and the bottom to obtain a given temperature gradient (around 300 °C) out of roughly a 15 mm height. Experiments conducted in different configurations (with or without samples) and the measurement of the associated thermal gradient led to improvements of the mould (in particular the introduction of a counter-piston). By th…
Development of high entropy tungsten-based alloys by powder metallurgy processes
2022
Although metallurgy is a very old research domain, many innovations are still being considered, such as the emergence of high-entropy alloys. These alloys, composed of at least three elements, are characterized by a chemical composition without a majority element and most of the time equimolar. Research in this field is very recent since the first studies concerning these alloys are from the early 2000s. The original chemical compositions of these alloys open the way to many possibilities to obtain unusual properties.In conjunction with these developments, powder metallurgy processes are expanding quickly because of the advantages they offer over more traditional techniques (foundry and for…
Spark plasma sintering of zirconia/nano-nickel composites
2015
Open Access
Spark plasma synthesis from mechanically activated powders: a versatile route for producing dense nanostructured iron aluminides
2004
Abstract The possibility of mechanically activated spark plasma sintering (MASPS) to perform simultaneously within a very short period of time the synthesis and the consolidation of nanophase iron aluminide from mechanically activated powders of Fe and Al in two different ratio (Fe53 at.% and Fe60 at.%) were confirmed in this work.
Bulk FeAl nanostructured materials obtained by spray forming and spark plasma sintering
2007
Abstract This paper examines the efficiency of two consolidation processing techniques high velocity oxy-fuel (HVOF) spray forming and spark plasma sintering (SPS) which allow to obtain bulk dense nanostructured materials. An oxide dispersion strengthened (ODS) Fe–40Al (at.%) based milled powder (with a nanostructure
Construction of two large-size four-plane micromegas detectors
2015
We report on the construction and initial performance studies of two micromegas detector quadruplets with an area of 0.5 m$^2$. They serve as prototypes for the planned upgrade project of the ATLAS muon system. Their design is based on the resistive-strip technology and thus renders the detectors spark tolerant. Each quadruplet comprises four detection layers with 1024 readout strips and a strip pitch of 415 $\mu$m. In two out of the four layers the strips are inclined by $\pm$1.5$^{\circ}$ to allow for the measurement of a second coordinate. We present the detector concept and report on the experience gained during the detector construction. In addition an evaluation of the detector perfor…
On the effects of the supporting frame on the radiation-induced damage of HCLL-TBM structural material
2007
Within the European Fusion Technology Programme, research activities have been conducted on the Helium-Cooled Lithium Lead (HCLL) breeding blanket concept with the aim of manufacturing a Test Blanket Module (TBM) to be irradiated in ITER. HCLL-TBM is planned to be located in an ITER equatorial port, housed inside an AISI 316 stainless steel-supporting frame. Since that frame has been designed to provide two positions separated by a dividing plate and the HCLL-TBM is expected to fill one of them, its nuclear response could vary depending on the filling status of the other position and on the plate thickness. A parametric study has been carried out to investigate the potential effects on the …
Big Data in Emergency Management: Exploitation Techniques for Social and Mobile Data
2020
The Internet of Things, crowdsourcing, social media, public authorities, and other sources generate bigger and bigger data sets. Big and open data offers many benefits for emergency management, but also pose new challenges. This chapter will review the sources of big data and their characteristics. We then discuss potential benefits of big data for emergency management along with the technological and societal challenges it poses. We review central technologies for big-data storage and processing in general, before presenting the Spark big-data engine in more detail. Finally, we review ethical and societal threats that big data pose.
Dermoscopy of a Spark’s Nevus
2018
Spark's nevus is a particular type of melanocytic nevus that on histology shows features of both Spitz's and Clark's nevus. Clinically, it is an asymmetric, irregular, multicolored, pigmented lesion that is not clearly distinguishable from melanoma or dysplastic (Clark's) nevus. Dermoscopic features have not been described yet, and one could speculate that they are similar to those of Clark's nevi because the histopathologic architecture of Spark's nevus is similar to that of a Clark's nevus, resembling Spitz's nevi in the epithelioid morphology of melanocytes. We present a 32-year-old woman with a Spark's nevus, who upon dermoscopy showed a pronounced atypical network with accentuation of …
Possible pulsed gamma ray emission above 50 MeV from the Crab pulsar.
1970
A SEARCH for pulsed gamma ray emission from NP 0532 has been carried out with a balloon-borne experiment using a spark chamber as the central detector. This pulsar, situated in the Crab Nebula, is already known to pulsate in the radio, optical and X-ray range1–5.